Author: Wang Shize, Wang Shaoqing, Ran Qingxuan, etc.
Author Unit: Shijiazhuang Railway University
Source of the article: Welded pipe
The electrochemical corrosion resistance of TB5 titanium alloy for offshore oil drilling and the pipeline is optimized, The effects of conventional solution and aging heat treatment on its electrochemical corrosion behavior were studied. The experimental results show that the grain size of TB5 titanium alloy increases gradually with the increase of solution temperature. The grain size after solution treatment at 950 ℃ is 125 larger than that after solution treatment at 800 ℃ μ m. The lower the solution temperature, the smaller the grain size, and the better the corrosion resistance;
The corrosion resistance of the alloy is significantly improved after aging, and the secondary corrosion resistance increases with the increase of aging temperature α The content of the phase increased first and then decreased, and the corrosion resistance of the alloy was similar to that of the secondary phase α It is directly proportional to the phase content.
The results show that the best heat treatment process with electrochemical corrosion resistance is 800 ℃ solid solution + 500 ℃ aging, and the corrosion rate is 1.44 × 10-3 mm/a。
Key words: TB5 titanium alloy /heat treatment /microstructure /corrosion resistance
Chemical composition of TB5 titanium alloy (%)
Heat treatment process parameters of TB5 titanium alloy
TB5 test sample | Solid solution Temperature/ ˚ C | Solid solution Time/h | Aging Temperature/ ˚ C | Aging Time/h |
A test sample | 800 | 1 | 400 | 1 |
B test sample | 800 | 1 | 450 | 1 |
C test sample | 800 | 1 | 500 | 1 |
D test sample | 800 | 1 | 550 | 1 |
F test sample | 800 | 1 | - | - |
E test sample | 850 | 1 | - | - |
G test sample | 950 | 1 | - | - |
XRD pattern of TB5 titanium alloy after heat treatment
Partially enlarged view of XRD
Metallographic photos of TB5 titanium alloy after solution treatment
Metallographic photos of 800 ℃ solid solution sample after aging treatment
Tafel test data of samples with different heat treatment temperatures
Impedance spectra of TB5 titanium alloy in 3.5% NaCl solution
